Luminaire associate status transponder

ABSTRACT

Monitoring street lighting infrastructure using special signaling devices and techniques for locating key components of the infrastructure and assessing their status. The integrity of common powerline connections may also be assessed.

BACKGROUND

This application is a non-provisional of and claims the benefit of U.S.Provisional Patent Applications Ser. Nos. 61/907,069, 61/907,078,61/907,090, 61/907,114, 61/907,133, 61/907,150, 61/907,168, 61/907,188and 61/907,210 filed on Nov. 21, 2013, the entire contents of which areincorporated herein by reference.

The ability to quickly discover the location and health and operationalstatus of individual street lamps is important to many infrastructureowners and operators. Many urban utilities have come to rely ondatabases for recording the locations of their lighting control systemassets, in particular the individual luminaires and the controls andconnections, the luminaire associates, which interface the luminaireswith the powerline. These data bases help the infrastructure owners andoperators manage their operations including street lightingaugmentation, maintenance, asset relocation, and control. Otherfunctions that depend on knowing the accurate location of individualstreet lamps include billing and inventory and maintenance recordation.

Occasionally a street lighting asset, in particular a luminaireassociate, will be relocated without appropriately noting the asset'srelocation in the infrastructure's database. This omission may lead to avariety of problems including costly maintenance crew searches for therelocated asset. There is therefore a need for detecting that aluminaire associate has been relocated and to determine its new locationin the lighting system.

Issues that may affect the infrastructure of lighting systems includethe timely notification of existing, or developing, health oroperational problems with individual luminaires and their respectiveluminaire associates. In some cases, maintenance crews need to drive toor near luminaires to check on their status. The dispatch of maintenancecrews for this purpose is costly and time consuming and becomes evermore so as the lighting system is expanded. There is therefore a need toinstantiate a technique whereby the infrastructure owner and operatorcan more quickly determine existing or developing health or operationalproblems with individual luminaire associates with less involvement ofmaintenance crews.

SUMMARY

An interrogation device is provided that is configured to sendinterrogation signals to one or more addressable transponders using acommon powerline for transmissions. The distance between theinterrogating device and the addressable transponder is determined bymeasuring the time to receive a response from the addressabletransponder following its interrogation. The interrogation and responsesignaling are carried on the common powerline.

BRIEF DESCRIPTION OF ILLUSTRATIONS

FIG. 1 illustrates the segmentation of a lighting fixture according toone embodiment.

FIG. 2 illustrates a linear installation of lighting fixtures accordingto one embodiment.

FIG. 3 illustrates a more topographically complex installation oflighting fixtures according to one embodiment.

FIG. 4 illustrates adding an additional interrogator unit according toone embodiment.

DETAILED DESCRIPTION

The location and health and operational status of individual streetlamps is important to many infrastructure owners and operators. Manyurban utilities rely on databases maintained by their lighting controlsystem operations center for recording the locations of their lightingcontrol system assets. These assets may include individual luminairesand their luminaire associates. Luminaire associates comprise controlsand connections that interface with the luminaires with the powerline.These databases help the infrastructure owners and operators managetheir operations. These operations include planning for street lightingaugmentation, maintenance, asset relocation, and controls. Otherfunctions that depend on knowing the accurate location of individualstreet lamps include billing, inventory auditing, and maintenancerecordation. This application teaches a method, system, and devices foraiding the lighting control system operations center in keeping itsdatabases current and correct.

An embodiment of the invention is illustrated in FIG. 1. The lightingfixture 100 comprises a lamp or luminaire 110, supported by a luminaireassociate 120. The luminaire associate 120 comprises electroniccomponents, electrical circuitry, and mechanical couplings associatedwith the mounting and control of the luminaire 110. The luminaireassociate 120 may be mounted atop a pole 130 that also provides aconduit for the powerline 140 serving the luminaire associate 120 andthe luminaire 110.

In one embodiment, one or more interrogation devices are coupled to thepowerline 140 that is common to a plurality of individual lightingfixture 100. An interrogation signal is placed on the powerline 140 byan interrogator device and travels to an addressed transponder. Thelighting fixtures 100 may contain addressable transponders. Thetransponder that is addressed transponds by placing a response signal onthe powerline 140. The interrogator device measures the time to receivethe response signal and estimates the distance from the interrogator tothe transponder.

Although the speed of signal propagation on the powerline 140 is asignificant fraction of the speed of light in free space, the speed ofsignal propagation on the powerline is dependent on many parameters. Itmay be therefore advisable to occasionally measure the speed of signalpropagation on the powerline 140 in order to validate or improve theestimation of distance. This may be done in several ways. By way ofexample, this may be done by measuring the time it takes after aninterrogator unit sends the interrogation signal until and a response isreceived by a fixed reference transponder, a transponder whose positionis known and invariant. Then that time is divided by two because of theround trip time of signal propagation.

FIG. 2 illustrates a linear installation of lighting fixtures 201-205each configured similarly to lighting fixture 100 discussed in relationto FIG. 1. Lighting fixtures 201-205 are connected to a common powerline140 along with an interrogation unit 210. The interrogation unit 210contains computational hardware and software used in signal generation,transmission, reception and decoding. Also illustrated in connected tocommon powerline 140 is a fixed reference responder 211. Theinterrogator unit 210 places an interrogation signal on the power line140 that is uniquely addressed to a transponder contained in either thefixed reference responder 211 or one of the luminaire associates 120.The addressed transponder responds to the interrogator unit 210. Theaddressed transponder may be a particular one of the luminaireassociates 120 within lighting fixtures 201-205. The interrogator unit210 measures the time duration between sending an interrogation signalto a particular luminaire associate and receiving the receiving theresponse signal from that particular luminaire associate. Theinterrogator may calculate the distance to the particular luminaireassociate. In this manner, the interrogator unit 210 can discover thedistances to the five lighting fixture 201-205 as displayed in Table 1.

TABLE 1 Lighting fixture distances to interrogator unit 210 Distance toLighting interrogator unit Fixture 210 201 1 202 2 203 3 204 4 205 5

The distances in Table 1 are all distinct and because the installationof lighting fixtures is linear and spacing of street lightssubstantially similar as depicted in FIG. 2, the positions of theindividual lighting fixtures in the linear installation is unambiguouslydeterminable.

More complex scenarios are expected in practice, such as thatillustrated in FIG. 3. In FIG. 3 there is a power line branch 141connected to power line 140. There are two lighting fixtures, 206 and207, on power line branch 141. In the example illustrated in FIG. 3 theinterrogation unit's distance to the seven lighting fixtures isdiscovered and displayed in Table 2.

TABLE 2 Lighting fixture distances to interrogator unit 210 Distance toLighting interrogator unit Fixture 210 201 1 202 2 203 3 204 4 205 5 2064 207 5

As seen in Table 2, the various lighting fixture distances to theinterrogator unit 210 are not distinct. The pair of lighting fixtures204 and 206, and the pair of lighting fixtures 205 and 207, exhibitidentical distances to the interrogator unit 210. Thus lighting fixture204 could have been swapped with lighting fixture 206 or lightingfixture 205 could have been swapped with lighting fixture 207 withoutprovoking a difference in the values displayed in Table 2. The lightingfixture positions are therefore not uniquely discoverable on thelighting fixture layout illustrated in FIG. 3 solely by the informationin Table 2.

The individual lighting fixture positions may be made uniquelydiscoverable by using a plurality of interrogator units positioned atdifferent points on the common powerline. FIG. 4 illustrates anadditional interrogator unit 220 with connection to the power linebranch 141 by the conductor 142. For the lighting fixture layout exampleillustrated in FIGS. 3 and 4, the distances from two interrogator units210, 220 to the seven lighting fixtures is displayed in Table 3.

TABLE 3 Lighting fixture distances to interrogator units 210 and 220Distance to Distance to Lighting interrogator unit interrogator Fixture210 unit 220 201 1 5 202 2 4 203 3 5 204 4 6 205 5 7 206 4 2 207 5 1

The pairs of individual lighting fixture distances to the two positioninterrogator units 210, 220 are all unique and, therefore, theindividual lighting fixture positions on the lighting fixture layoutillustrated in FIGS. 3 and 4 are uniquely discoverable.

In general, the individual lighting fixture positions may be madeuniquely discoverable by using P interrogator units connected to thepowerline at various points so that each P-tuple value of the lightingfixture distances from each position interrogator unit to each of thelighting fixtures on the common powerline are unique.

In addition to estimating distances on the powerline 140, the responseof a transponder located in a luminaire associate 120 of a lightingfixture may also report on the status of the of the luminaire 110 andthe luminaire associate 120 of that lighting fixture. One embodiment ofthis technique is to append the status information to the transponderresponse signal. The status of a luminaire associate 120 may comprisedata reporting on operationally important luminaire electricalparameters such as voltage, current, wattage, and real power, and otherdata including data characterizing the output of luminaire 110. Thestatus may also include a condition status placed in the luminaireassociate 120 by a maintenance crew reporting on servicing details.

As presented, the distance between an interrogating unit and atransponder is estimated by the interrogating unit's sending aninterrogation signal though a communication medium to the transponder.The transponder responds upon reception of the interrogation signal. Theinterrogating unit receives the transponder signal and uses the roundtrip time from interrogation signal transmission to reception oftransponder response and the speed of signal propagation through thecommunication medium to estimate the distance between them. The accuracyof the estimated distance is dependent on the time-bandwidthcharacteristic of the signaling waveforms used by the interrogator andthe transponder.

For an example relevant to this application, the distance of aninterrogating unit to a transponder via a common powerline 140 may beestimated using signaling waveforms of sufficient time-bandwidth. Aproblem with using a short-time very high bandwidth signal is that thepowerline may not be capable of supporting signaling that has a veryhigh bandwidth. Pulse compression signaling may be used to obviate thislimitation.

Pulse compression is a technique well known in the art of signal designwhereby a signal may be crafted to achieve a large time-bandwidthproduct by increasing the signaling time with concomitant maintenance ofbandwidth. For an example, a basic signal s(t) of period T-time unitsthat has a power spectrum whose maximum significant frequency is at orbelow the maximum frequency that the powerline will support forsignaling purposes. A common technique is to build a signal s(t) bychoosing a T-time units long segment of a sine wave having many periods.The signal s(t) is then multiplied by a sequence of plus and minus onessuch that an autocorrelation is created characterized by a sharp spikearound the zero-offset point of the autocorrelation and low magnitudesidelobes. The sequence of plus and minus ones and the segment of thesine wave of many periods may be aligned so that transition times of thesequence of plus and minus ones align with zero crossings of the segmentof the sine wave of many periods.

The interrogation signal formed for this example may be built byconcatenating one or more periods of s(t) followed by one period of s(t)inverted, denoted as s(t), followed by N periods, each of length T-timeunits, and each period comprising either s(t) or s(t). Signaling in thismanner allows an addressable transponder to: recognize, by the receptionof one or more s(t) basic signals, that an interrogation message hasbegun; then note, by the first occurrence of s(t), that the address ofthe addressable transponder is to follow by the next N periods of s(t)and s(t); and then derive the address of the addressed transponder bydecoding an occurrence of s(t) as a zero and an occurrence of s(t) as aone.

The addressed transponder then responds with a signal built byconcatenating one or more periods of s(t) followed by one period of s(t)inverted, denoted as s(t), followed by N periods, each of length T-timeunits, and each period consisting of s(t). This example signaling formatmay also appear as an interrogator unit addressing a transponder with anaddress of all zeros. Embodiments are envisioned that avoid thisambiguity by not allowing any transponder to be assigned an address ofall zeros.

If the addressed transponder is located in a fixed reference responder211, the fixed reference transponder 211 ceases transponding aftersending the above response as the fixed reference transponder 211 willnot be reporting status. If the addressed transponder is located in aluminaire associate 120, the addressed transponder continues the abovetransmission by concatenating M periods, each of length T-time units,and each period comprising either s(t) or s(t). These M bits inform theinterrogator of one of 2^(M) conditions reportable by the luminaireassociate where the addressed transponder is located.

In an embodiment, more than one interrogation units 210 are connected tothe common powerline 140. A signaling protocol may be instituted toprevent any interrogation signaling and the responses that are generatedfrom overlapping. There are many suitable candidate protocols known inthe art including transmission sensing, collision avoidance, andnon-overlapping time-based slots, with guard times as prudent, assignedto each interrogator unit.

Data respecting the distances for the lighting fixture to interrogatorunits that are discovered and status information reported bytransponders located in luminaire associates are forwarded to thelighting control system operations center.

An exemplary technical effect of the methods and systems describedherein includes: (a) generating a melt pool based on the buildparameters of the component; (b) detecting an optical signal generatedby the melt pool to measure the size or the temperature of the meltpool; and (c) modifying the build parameters in real-time based on thesize or the temperature of the melt pool to achieve a desired physicalproperty of the component.

Some embodiments involve the use of one or more electronic or computingdevices. Such devices typically include a processor or controller, suchas, without limitation, a general purpose central processing unit (CPU),a graphics processing unit (GPU), a microcontroller, a fieldprogrammable gate array (FPGA), a reduced instruction set computer(RISC) processor, an application specific integrated circuit (ASIC), aprogrammable logic circuit (PLC), and/or any other circuit or processorcapable of executing the functions described herein.

The methods described herein may be encoded as executable instructionsembodied in a computer readable medium, including, without limitation, astorage device, and/or a memory device. Such instructions, when executedby a processor, cause the processor to perform at least a portion of themethods described herein. The above examples are exemplary only, andthus are not intended to limit in any way the definition and/or meaningof the term processor.

Exemplary embodiments for enhancing the build parameters for makingadditive manufactured components are described above in detail. Theapparatus, systems, and methods are not limited to the specificembodiments described herein, but rather, operations of the methods andcomponents of the systems may be utilized independently and separatelyfrom other operations or components described herein. For example, thesystems, methods, and apparatus described herein may have otherindustrial or consumer applications and are not limited to practice withelectronic components as described herein. Rather, one or moreembodiments may be implemented and utilized in connection with otherindustries.

Although specific features of various embodiments of the invention maybe shown in some drawings and not in others, this is for convenienceonly. In accordance with the principles of the invention, any feature ofa drawing may be referenced or claimed in combination with any featureof any other drawing.

This written description uses examples to disclose the invention,including the best mode, and to enable any person skilled in the art topractice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

1. A method for interrogating transponders located within devices atdistinct locations on a powerline commonly connected to the addressabletransponders comprising the steps of: transmitting an interrogationsignal by at least one interrogation device on the powerline, theinterrogation signal being addressed to an addressable transponder;receiving a response signal on the powerline from the addressabletransponder; electronically measuring a time period between receivingthe response signal and transmitting the interrogation signal; andelectronically estimating a distance to the addressable transponder byusing the time period measured to receive the response signal.
 2. Themethod of claim 1 further comprising the step of using pulse compressionsignaling for generation of the interrogation and the response signals.3. The method of claim 1 wherein the addressable transponder is locatedin a luminaire associate or in a fixed reference responder.
 4. Themethod of claim 3 wherein the step of electronically estimating furthercomprises using the electronically measured time to receive a responsefrom the fixed reference responder to improve the estimation ofdistance.
 5. The method of claim 3 further comprising the step ofelectronically deriving status of the luminaire associate by furtherprocessing the received response by the at least one interrogationdevice.
 6. The method of claim 3 further comprising the step offorwarding the estimated distance of a particular luminaire associatefrom the one or more interrogation devices to a lighting control systemoperations center.
 7. The method of claim 3 further comprising the stepof forwarding the electronically derived status of the luminaireassociate by the interrogation devices to a lighting control systemoperations center.
 8. A system for electronically estimating thedistance between a powerline interrogator and an addressable transponderboth connected to a common powerline comprising: an interrogation signalgenerator within the powerline interrogator that generates and transmitsan interrogation signal addressed to the addressable transponder; areceiver within the addressable transponder that recognizes theinterrogation signal addressed to the addressable transponder; atransmitter within the addressable transponder that sends a response tothe powerline interrogator after recognizing receipt of theinterrogation signal addressed to the addressable transponder; anelectronic timer within the powerline interrogator to measure the timerequired to receive the response from the addressable transponder; andan electronic calculator within the powerline interrogator to estimatethe distance to the addressable transponder by using the measured timerequired to receive the response.
 9. The system of claim 8 wherein theaddressable transponder is located in a luminaire associate or in afixed reference responder.
 10. The system of claim 9 wherein thepowerline interrogator electronically derives the status of theluminaire associate by further processing the response received from theaddressable transponder located in the luminaire associate.
 11. Thesystem of claim 9 wherein the electronically measured time to receive aresponse from the fixed reference responder is used to validate orimprove estimation of distance.
 12. The system of claim 9 wherein theestimated distance to the addressable transponder in a luminaireassociate is forwarded to a lighting control system operations center.13. The system of claim 12 wherein the status of the luminaire associateis forwarded to the lighting control system operations center.
 14. Asystem for interrogating transponders on a common powerline comprising:a first device that generates and transmits an interrogation signal onthe common powerline, the interrogation signal addressed to atransponder; and a second device containing a transponder that sharesthe common powerline and generates a response to the interrogationsignal and places the response on the common powerline.
 15. The systemof claim 14 wherein the first device uses pulse compression signaling.16. The system of claim 15 wherein the second device is selected from: aparticular luminaire associate out of a plurality of luminaireassociates; or another device that has a known fixed location thatgenerates and transmits interrogation signals.
 17. The system of claim16 wherein the second device uses pulse compression signaling.
 18. Thesystem of claim 17 further comprising: a computational elementoperatively coupled to the first device; a receiver operatively coupledto the first device that receives the response from the commonpowerline; a timer associated with the first device that measures a timeperiod between receiving the response of and transmitting theinterrogation signal; and a calculator associated with the first deviceto estimate a distance between the first device and the second deviceusing the time period.
 19. The system of claim 16 wherein the seconddevice is located in a luminaire associate that exists with a uniqueaddress within a plurality of luminaire associates.
 20. The system ofclaim 19 further comprising the response including an electronicallyderived status of the luminaire associate.